1. Field of the Invention
The present invention relates to a surface mount antenna that can be mounted on a circuit substrate, a method of manufacturing the same, and a communication device.
2. Description of the Related Art
Surface mount antennas that can be mounted on a circuit substrate have been used in the past. These surface mount antennas include, for example, a dielectric substrate in chip form and at least one radiation electrode operating as an antenna, the radiation electrode being disposed on the dielectric substrate. Two known methods of manufacturing surface mount antennas are described below. According to one method, an electrode is formed on the surface of the dielectric substrate by plating or the like. Then, this electrode is subjected to etching, whereby the radiation electrode is formed. According to the other method, a thick-film paste is formed on the surface of a dielectric substrate by printing so as to have the form of the radiation electrode. Then, the thick-film paste is dried and fired, whereby the surface mount antenna is formed.
The above-described techniques are disclosed in Japanese Unexamined Patent Application Publication Nos. 2001-119224 and 8-18329.
In general, the known surface mount antennas have a small substrate. However, the radiation electrodes are individually formed on the small substrates. Since it is difficult to form the radiation electrodes on the small substrates, the efficiency of manufacturing the surface mount antennas reduces and the cost thereof increases.
The dielectric constants and sizes of the dielectric substrates often vary slightly, which often causes variations in resonance frequencies of the radiation electrodes on the dielectric substrates. Therefore, the dimensions of the radiation electrodes must be adjusted with high precision to reduce these variations, considering the dielectric constants and the sizes thereof. However, since the radiation electrodes are small, it has been difficult to form the radiation electrodes to have precise dimensions.
Further, the form and dimensions of the radiation electrode and the dimensions of the dielectric substrate or other elements must be redesigned to change the resonance frequency of the radiation electrode, which requires much time and effort.